DE102012110701A1 - Heat exchanger for a refrigerant circuit - Google Patents

Abstract

The invention relates to a bidirectional heat exchanger (1) of a refrigerant circuit of an air conditioning system of a motor vehicle. The air conditioning system is designed for combined operation in refrigeration and heating mode and the heat exchanger (1), the direction of flow of the refrigerant being dependent on the operating mode. A first, multi-flow heat exchanger (1) has manifolds (2, 3), flow paths which are each assigned to a flow, and means for dividing the inner volume of at least one manifold (2, 3) into independent areas. The first flow of the heat exchanger (1) is designed with a larger flow cross-section and a larger heat transfer surface than the last flow. In a second heat exchanger (1), a refrigerant passage (4) with a connection block (28) for connecting a refrigerant line (27) is formed, with one as an additional fluid connection to the refrigerant passage between the collecting pipe (2) and the connection block (28) (4) formed short-circuit line (29) is arranged. The invention also relates to a device for subdividing the inner volume of a collecting pipe (2, 3) of a heat exchanger (1). Inside the manifold (2, 3) there is at least one movable separating element (13, 13 ') which is based on the differential pressure principle and, depending on the orientation within the manifold (2, 3) and the pressure difference present, opens or closes an opening.

Description

The invention relates to a heat exchanger of a refrigerant circuit of an air conditioning system of a motor vehicle. The heat exchanger has manifolds and is formed mehrflutig and bidirectional flow. The air conditioner is intended for combined operation in refrigeration and heating modes. The flow direction of the refrigerant inside the heat exchanger depends on the operating mode. The invention further relates to a device for dividing the inner volume of the manifold and for the flow deflection of the fluid in the manifold of a heat exchanger.

Conventional air conditioning systems in motor vehicles are designed as combined refrigeration system and heat pump systems. The heat exchanger provided in the cooling system mode as a condenser for dissipating heat from the refrigerant to the ambient air is operated in the heat pump mode as an evaporator for absorbing heat from the ambient air.

According to the prior art, heat exchangers used as condensers are designed as multi-flow heat exchangers, for example with a subcooling section and an integrated high-pressure collector. In the refrigerant circuit of automotive air conditioning systems, the capacitors usually have two or four floods. The heat-transferring surface is formed from flat tube profiles, which are connected on the air side by means of ribs. In the manufacture of the heat exchanger, the flat tube profiles are inserted and soldered on the refrigerant side with both ends in slotted headers. For deflecting the direction of the refrigerant mass flow separating elements are provided. In the outside of the manifold, a slot is introduced into the wall at the position of the desired deflection, for example by milling or punching, and closed the flow cross-section of the manifold with a stamped plate. The plate corresponds to the separating element. By means of the use of the separating elements, the heat exchanger is divided, for example, into two or four subregions, the so-called floods. The use of a number n separating elements causes the distribution of the heat exchanger refrigerant side in a number of n + 1 floods. Especially in heat exchangers, which are used as condensers when operating in the refrigeration system mode of air conditioners, belongs in systems with thermostatic expansion valves arranged between the penultimate and the last high-pressure accumulator to the prior art. The collector is arranged on the capacitor. In the collector, the phases of the almost completely condensed refrigerant are separated from each other. The separated liquid refrigerant then flows through the last flood of the condenser. The last flood is thus preferably applied with liquid refrigerant, which has a significantly higher density than the gaseous refrigerant and a smaller flow area than the two-phase mixture needed. For this reason, in the prior art, the last tide is formed as subcooling with significantly less flat tubes than the previous tides. In addition, the condenser may include a filter screen and a desiccant.

When operating the refrigerant circuit in the heat pump mode, the same heat exchanger is used as evaporator. In this case, the refrigerant is expanded to a pressure level whose associated saturation temperature is lower than the temperature of the ambient air. The refrigerant absorbs heat from the ambient air and evaporates. The expanded two-phase refrigerant flows through the original subcooling section and evaporates. This section of the now operated as an evaporator heat exchanger, which is actually designed for the flow with liquid refrigerant and significantly greater density with a small number of flat tubes and thus smaller flow cross-section will have a very high pressure drop in heat pump mode, as with increasing evaporation, the density of the refrigerant reduced. Due to the low pressure level, the density of the refrigerant when operating in the heat pump mode on the low pressure side of the refrigerant circuit is very low, so that additional flow pressure losses significantly affect the performance and efficiency of the heat pump system negative.

In addition, when operating heat pumps with a refrigerant circuit and ambient air as the heat source at ambient temperatures of less than 0 ° C, the risk of icing of the heat transfer surfaces of the operated as an evaporator heat exchanger. The multi-flow construction of the heat exchanger, which causes high refrigerant side pressure drops due to the low suction density of the refrigerant, leads to an additional lowering of the surface temperature of the heat exchanger and thus to an increase in the risk of icing.

There are arrangements of components in refrigerant circuits are known in which the formed for the application of external air heat exchanger is operated on the refrigerant side with changing flow direction. In this case, the heat exchanger is acted upon such that the refrigerant is flowed through during operation in the refrigeration plant mode as a condenser in a first flow direction, while the heat exchanger during operation in the Heat pump mode is flowed through as an evaporator in a second direction opposite to the first direction. The pressure losses of the refrigerant, in particular during operation of the heat exchanger as an evaporator in the heat pump mode, are thus reduced. The subcooling of the condenser in the refrigeration system mode is thus not flowed through in the heat pump mode with almost completely vaporized or even superheated refrigerant, but refrigerant in the two-phase state after relaxation with a much higher density. However, the disadvantageous very high pressure losses in the heat pump mode are only reduced and not reduced to an optimum.

From the state of the art also shows how with a bidirectionally flow-through integrated in the refrigerant circuit heat exchanger for heat transfer between the refrigerant and the ambient air icing of the heat transfer surfaces during operation in heat pump mode can be prevented control technology. The process of icing is avoided, for example, either by switching off the heat pump at ambient temperatures of less than 0 ° C or the refrigerant circuit is switched to defrost the heat exchanger from the heat pump mode in the refrigeration system mode and operated at least temporarily in the refrigeration system mode. However, the methods given lead to a very strong reduction in performance of the air conditioner.

In the EP 1 895 255 B1 For example, there is provided a heat exchanger assembly having two spaced, parallel manifolds between which a plurality of flow tubes extend and form a fluid connection with the manifolds for flowing a refrigerant between the manifolds. In the first manifold, a static separator is arranged, which divides the cavity of the manifold into a first and a second chamber with fixed portions. The heat exchanger assembly has terminals disposed on the manifolds and an external controller for switching between an evaporator mode and a capacitor mode. The connections are opened or closed in such a way that the refrigerant circulates in the evaporator mode in single-flow and in the condenser mode in multiple-flow through all flow tubes. The heat exchanger arrangement can also be flowed twice in the evaporator mode, for example, in which case more than two passages are flowed through in the condenser mode.

The object of the present invention is to provide and improve a heat exchanger with which maximum heat outputs can be transmitted with minimal space requirements, both during operation in the refrigeration system mode and during operation in the heat pump mode. In this case, the refrigerant-side pressure loss is to be optimized, also to minimize the risk of icing when operating in heat pump mode. The subcomponents as well as the manufacturing process of the heat exchanger should not cause any additional costs compared to known systems. In this case, the heat exchanger should also be designed for the use of control technology to prevent icing.

The object is achieved by a heat exchanger according to the invention, which is designed as a component of a refrigerant circuit of an air conditioning system of a motor vehicle. The air conditioner is intended for combined operation in refrigeration and heating modes. The heat exchanger has a first and a second manifold, a first and a second refrigerant passage for flowing through the refrigerant, a plurality of flow paths and means for dividing the inner volume of at least one collecting tube into independent regions. The headers are spaced, aligned parallel to each other. The flow paths are formed as mutually parallel fluid connections between the headers and each associated with a flood. The heat exchanger is formed mehrflutig and bi-directionally permeable, wherein the flow direction of the refrigerant in the interior of the heat exchanger is dependent on the operating mode of the air conditioner. The flow direction of the refrigerant in the refrigeration system mode is directed opposite to the flow direction of the refrigerant in the heat pump mode. Depending on the direction of flow of the refrigerant and the area under consideration within the collecting tube, the collecting tubes also serve as distributors of the refrigerant to the different flow paths. The headers can, according to their differentiated function, also referred to as distribution pipes. According to the concept of the invention, the first flow of the heat exchanger in the flow direction of the refrigerant in the refrigeration system mode has a larger flow cross-section and a larger heat transfer surface than the last flood. In addition, the first refrigerant passage for flowing the refrigerant in the flow direction of the refrigerant in the refrigeration system mode is formed with a larger or equal flow cross section as the second refrigerant passage for discharging the refrigerant.

The heat exchanger is preferably designed as a refrigerant-air heat exchanger: for supplying heat from the ambient air to the refrigerant and for dissipating heat from the refrigerant to the air or ambient air to be supplied to the passenger compartment. In the refrigeration system mode first Operating mode of the air conditioner, the heat exchanger is operated as a condenser / gas cooler. In heat pump mode with ambient air as the heat source of the heat exchanger is acted as evaporator with refrigerant. The heat exchanger can be formed without subcooling and arranged in a refrigerant circuit without a collector. The refrigerant can flow through at least two floods of the heat exchanger in the refrigeration system mode.

According to one embodiment of the invention, the first refrigerant passage for the inflow of the refrigerant when operating in the refrigeration system mode has an inner diameter of greater than 8 mm. The diameter is preferably in a range of 10 mm to 14 mm. According to a further embodiment of the invention, the second refrigerant passage for discharging the refrigerant when operating in the refrigeration system mode has an inner diameter of greater than 6 mm. The diameter is preferably in a range of 6 mm to 19 mm.

The object is also achieved by a heat exchanger according to the invention of a refrigerant circuit of an air conditioning system of a motor vehicle, which has a manifold, parallel flow paths and at least two refrigerant passages. The heat exchanger is bi-directionally permeable and the flow direction of the refrigerant inside the heat exchanger is dependent on the operating mode of the air conditioning. Depending on the flow direction, the refrigerant flows through the flow paths, the collecting pipe and the refrigerant passage or the refrigerant passage, the collecting pipe and the flow paths one after the other. The refrigerant passage is formed on the opposite side to the collecting pipe side with a connection block for connecting a refrigerant pipe of the refrigerant circuit. According to the concept, a short-circuit line is arranged between the collecting tube and the connection block as an additional fluid connection to the refrigerant passage. The short-circuit line thus represents a connection parallel to the refrigerant passage between the manifold and the terminal block.

The headers of the heat exchanger according to the invention are preferably vertically aligned and arranged horizontally spaced from each other. The flow paths are horizontally aligned and arranged vertically spaced from each other. The individual flow paths arranged as fluid connections between the headers are advantageously formed from flat tube profiles. The flat tube profiles have a depth of less than 20 mm. The depth of the flat tube profiles is preferably in a range of 10 mm to 18 mm. According to one embodiment of the invention, ribs are arranged on the air side between the flat tube profiles, which have the same depth as the flat tube profiles. Under the depth of the dimension of the flat tube profiles in the flow direction of the air and perpendicular to the longitudinal direction in which the fluid flows, to understand. The headers are advantageously formed in one or two parts and have a diameter or a width which is greater than the depth of the flat tube profiles.

Depending on the operating mode of the air conditioning system and thus dependent on the flow direction of the refrigerant through the heat exchanger, the different number of floods traversed by the refrigerant is advantageously adjusted in order to minimize the refrigerant side pressure losses and thus reduce the risk of icing of the heat transfer surface when operating in heat pump mode. In addition, the transmitted heat output is optimized during operation in the refrigeration system mode.

According to a first alternative embodiment of the invention, the heat exchanger is formed in a double-flow configuration, wherein the ratio of the number of flat tube profiles of the first flow to the second flow is in the range from 3 to 5 in the flow direction of the refrigerant in the refrigeration system mode. The ratio is preferably in a range of 3.5 to 4.5.

According to a second alternative embodiment of the invention, the heat exchanger is designed to flow in four-flow, wherein in the flow direction of the refrigerant in the refrigeration system mode, the ratio of the numbers of flat tube profiles of successively flowed through flows 19: 13: 10: 6. The flat tube profiles advantageously have a depth in the range of 15 mm to 17 mm and a height in the range of 1.0 mm to 1.6 mm. Under the height while the dimension of the flat tube profiles perpendicular to the flow direction of the air and perpendicular to the longitudinal direction in which the fluid flows, to understand.

The object is further achieved by means of a device for dividing the inner volume of the manifold and for the flow deflection of the fluid in the manifold of a heat exchanger. According to the concept of the invention, at least one movable separating element is arranged within the collecting tube. The movement of the separating element is based on the differential pressure principle and the orientation of the separating element within the collecting tube. Depending on the applied pressure difference on the different sides and the orientation of the separating element, an opening as a passage for the fluid is released or closed by the separating element. The movable separating element has a rectilinearly movable closure element and a stop element. In the closed state, the closure element bears against the stop element. The closure element and thus the separating element are arranged in the direction of the vertically oriented collecting tube, which is also referred to below as the longitudinal direction.

The separating element is preferably formed in several parts with the stop element and the closure element. The stop element advantageously has an outer contour which corresponds to the inner contour of the collecting tube such that a narrow gap for soldering remains between the contours with a tolerance of +/- 0.1 mm, preferably +/- 0.05 mm.

According to a preferred embodiment of the invention, the stop element has an inner contour which forms an opening as a flow cross-section for the fluid. The opening is closed by the closure element in the closed state of the separating element. It is advantageous that the closure element is designed to be movable in a straight line in a longitudinal direction L.

According to a development of the invention, the separating element has means for guiding the movement of the movable closing element relative to the stop element. According to a first alternative embodiment, the inner contour of the stop element with formations and the closure element are formed with a guide element. The guide element preferably has the shape of a pin, which is arranged perpendicular to the plane spanned by the closure element in the longitudinal direction L extending on the closure element. The guide element is movably supported on the formations in the longitudinal direction L. The formations of the stop element and the guide element thus form a guide for the movable closure element. According to a second alternative embodiment, the separating element is formed with guide elements for guiding the movable closure element. The guide elements are arranged uniformly on the circumference of the inner contour of the stop element on the stop element and formed as a circle segments with a step. The inner contour is preferably formed as a circular opening. The circular arc-shaped surfaces of the step, which are aligned with the center of the circle and which rest on the stop element, are provided for guiding the movable closure element and correspond with the side surface of the closure element. The guide elements are also advantageously designed as a support and attachment of a second stop element for the closure element.

The second stop element is preferably arranged at the level of the step of the guide element spaced from the first stop element. The closure element is advantageously supported in the longitudinal direction movable between the stop elements and formed circular. On the outer circumference of the closure element openings are provided aligned in the longitudinal direction, which are particularly advantageously designed such that release at least one part of the opening release a passage for the fluid when abutment of the closure element on the stop element.

According to a further embodiment of the invention, the means for guiding the movement of the closure element are designed to prevent rotation of the closure element relative to the stop element.

According to the concept of the invention, the heat exchanger according to the invention is formed within a collecting tube with a device according to the invention for dividing the inner volume of the collecting tube and for the flow deflection of the fluid. The arrangement of the device, the flow cross-section and / or the heat transfer surface of the heat exchanger are dynamically changeable and can be adjusted depending on the operating mode and needs.

Preferred fluids are refrigerants as phase-changing heat carriers, such as carbon dioxide (R744), R134a, HFO1234yf or refrigerant mixtures.

• – Flachrohrprofile, Sammelrohre und Rippenstrukturen als Subkomponenten sowie das Herstellungsverfahren des Wärmeübertragers verursachen keine zusätzlichen Kosten,
• – in Bezug zu Wärmeübergang und Druckverlust optimierte Aufteilung der Wärmeübertragungsfläche im Kälteanlagen- und im Wärmepumpenmodus,
• – Minimierung des Risikos der Vereisung im Wärmepumpenmodus,
• – Vermeidung eines Leistungsverlustes der Klimaanlage beim Betrieb im Wärmepumpenmodus während des Abtauens,
• – Übertragung der maximalen Leistung an das Kältemittel,
• – Steigerung der Effizienz beim Betrieb eines (Zu-)Heizsystems, dabei Reduzierung des Kraftstoffverbrauchs und Erhöhung der Reichweite von Elektrofahrzeugen.

Further advantages of the heat exchanger or of the device for dividing the internal volume of the collecting tube of a heat exchanger compared with the prior art can be summarized as follows:

• - Flat tube profiles, manifolds and ribbed structures as subcomponents, and the manufacturing process of the heat exchanger do not incur additional costs
• Optimized distribution of the heat transfer surface in the refrigeration system and in the heat pump mode with respect to heat transfer and pressure loss,
• - minimize the risk of icing in heat pump mode,
• Avoidance of power loss of the air conditioner when operating in heat pump mode during defrosting,
• Transmission of the maximum power to the refrigerant,
• - Increasing the efficiency of operating a (Zu-) heating system, while reducing fuel consumption and increasing the range of electric vehicles.

Further details, features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Show it:

1 : double-flow heat exchanger as condenser / gas cooler in refrigeration system mode,

2 : static separating element for arrangement inside a manifold in different views,

3a : three-flow heat exchanger with separating elements in the manifold,

3b : closed, rectilinearly movable closure element of a separating element,

3c : opened, rectilinearly movable closure element of a separating element,

4a : Arrangement of a movable separating element in the first embodiment within a collecting tube,

4b : opened partition off 4a in front view,

4c : opened partition off 4a in rear view,

5a : movable partition element in the second embodiment in the installable state,

5b : Exploded view of the separating element 5a .

5c : Sectional view of the separating element 5a in the open state,

5d : Sectional view of the separating element 5a when closed,

5e : Construction sketch of the separating element 5a and

6 : Connection block on the first refrigerant passage of the first manifold with a short circuit line.

In 1 is a heat exchanger 1 shown in a double-flow design as a condenser / gas cooler in the refrigeration system mode according to the prior art. The heat exchanger 1 is preferably a component of a refrigerant circuit, not shown, of an air conditioning system of a motor vehicle. The gaseous refrigerant compressed by a refrigerant compressor passes through the first refrigerant passage at a high temperature 4 in the first manifold 2 of the heat exchanger 1 one. The first collection pipe 2 has a static separator 7 on which the manifold 2 divided into two independent and mutually sealed areas. The static separator 7 is designed for example as a sheet metal. In the upper area that is in the first manifold 2 introduced gaseous refrigerant evenly divided on different flow paths of the first tide. The flow paths are shown by arrows with solid lines. The refrigerant flows through the parallel flow paths in the flow direction 6 ^I from the first manifold 2 to the second manifold 3 , The flow channels or the partial mass flows of the refrigerant through which a divided refrigerant mass flow flows in parallel in the same direction are referred to as a flood. In this case, the partial mass flows of the refrigerant have substantially the same state parameters. This through the different flow paths in the second manifold 3 conducted refrigerant is in the second manifold 3 mixed again and then divided evenly on the different flow paths of the second tide. The refrigerant flows through the again parallel to each other arranged flow paths from the second manifold 3 to the first manifold 2 back. The refrigerant passed through the various flow paths becomes the lower portion of the first header 2 mixed again. The entire refrigerant mass flow passes through the second refrigerant passage 5 , which in the lower part of the first manifold 2 is arranged, from the heat exchanger 1 out. The cooled with release of heat and at least partially liquefied refrigerant is now liquid or two-phase. In addition, completely liquefied refrigerant may still be undercooled, that is to say have a temperature which is lower than the condensation temperature. The area ratios of the two floods are different with respect to the heat transfer areas and the cross-sectional areas of the flow paths due to the changing density of the refrigerant upon cooling and condensation.

2 shows a static separator 7 for arrangement within a manifold 2 . 3 According to the state of the art. The one-piece formed by stamping from a sheet metal, formed static separator 7 has a flat, closed trained surface 8th on, which completely from a border 9 is surrounded. The closed area 8th is with a smaller sheet thickness than the border 9 designed so that the border 9 on both sides of the closed area 8th is sublime. The static separator 7 is also in relation to a plane of symmetry 10 formed symmetrically. The border 9 has an outer contour, which takes into account tolerances of the inner contour of the manifold 2 . 3 recreated is. The border 9 is also equipped with a locking element 11 and a holding element 12 formed, which on the outer contour of the border 9 trained and on the plane of symmetry 10 are arranged. The locking element 11 is opposite to the holding element 12 aligned. The static dividers 7 be in the production of the heat exchanger 1 on the holding element 12 held and next to the flat tube profiles, which the flow paths of the refrigerant between the headers 2 . 3 form, in the slotted headers 2 . 3 plugged in. The locking element 11 serves to fix the separating element 7 inside the manifold 2 . 3 during production. After insertion of the separating elements 7 and the flat tube profiles in the headers 2 . 3 The individual components are soldered. The wide trained border 9 of the separating element 7 allows easy soldering. The static separator 7 closes the flow cross-section of the manifold 2 . 3 ,

In 3a is a three-flow heat exchanger 1 with dividers 13 in both headers 2 . 3 when operating in refrigeration system mode and in heat pump mode. Unlike the training to 1 are the dividers 13 movable while the separating element 7 out 1 is static. The flow direction 6 ^{I of} the refrigerant in the refrigeration system mode is indicated by arrows with solid lines, the flow direction 6 ^{II of} the refrigerant in the heat pump mode indicated by arrows with dashed lines. The headers 2 . 3 are each formed at their ends by means of a plug for sealing to the environment.

The separating elements 13 are switched so that the refrigerant, similar 1 , through the first refrigerant passage 4 in the first manifold 2 is guided and through the parallel flow paths of the first flood to the second manifold 3 flows. The separating element 13 in the first manifold 2 closes the manifold 2 such that the manifold 2 has two separate areas. The refrigerant is in the upper part of the second manifold 3 mixed and diverted into the second tide.

The second flood is flowed through by the refrigerant in the opposite direction of the first flood. The refrigerant is at the bottom of the first manifold 2 mixed and diverted into the third tide. Subsequently, the third flood is flowed through by the refrigerant in the parallel direction of the first flood, in the lower region of the second manifold 3 mixed and passes as a refrigerant mass flow through the second refrigerant passage 5 from the heat exchanger 1 out. In the refrigeration system mode, the refrigerant flows essentially from top to bottom through the three-way heat exchanger 1 , The area ratios of the floods, that is, the heat transfer surfaces and the cross-sectional areas of the flow paths are due to the changing density ratios of the refrigerant as it flows through the heat exchanger 1 customized.

Compared to the refrigeration system mode, the heat exchanger 1 in heat pump mode, one-flow from the refrigerant in the direction of flow 6 ^{II flows} substantially from bottom to top. The flow direction 6 ^{II of} the refrigerant in the heat pump mode is represented by arrows with dashed lines. The flow direction of the refrigerant in the heat pump mode may also be directed from top to bottom, while the refrigerant then flows in the refrigeration system mode from bottom to top.

The refrigerant passes through the second refrigerant passage 5 in the second manifold 3 of the heat exchanger 1 one. The separating element 13 in the second manifold 3 is open, that means the two in the manifold 3 trained areas are fluidly interconnected. The refrigerant is applied to all the manifolds 2 . 3 connecting flow paths of the heat exchanger 1 split so that the refrigerant is the heat exchanger 1 flows in one-flow. In the first manifold 2 in which the separating element 13 is also open and the two trained areas are fluidly connected to each other, the partial mass flows of the refrigerant are mixed together. Subsequently, the refrigerant flows through the second refrigerant passage 5 from the heat exchanger 1 out.

With the help of the formation of the separating elements 13 the number of successively flowed floods, for example in the refrigeration plant mode compared to the heat pump mode, is varied. The heat transfer surface and the flow cross section of the refrigerant are dynamically changeable and can be adapted to the respective operating states and external conditions.

The flow paths of the refrigerant between the headers 2 . 3 forming flat tube profiles have a profile depth of less than 20 mm, with profile depths of 16 mm ± 2 mm or 12 mm ± 2 mm are preferred. On the air side, the heat-transferring surface is formed by the flat tube profiles with ribs arranged therebetween. The ribs have the same profile depth as the flat tubes. In the formation of a double-flow heat exchanger 1 For example, flat tube profiles with a profile depth of 16 mm ± 2 mm or 12 mm ± 2 mm are used. The ratio of the number of flat tubes of the first flow to the number of flat tubes of the second flow in the direction of flow of the Refrigerant when operating in refrigeration mode is between 3 and 5. The preferred ratio is between 3.5 and 4.5. When forming a four-flow heat exchanger, for example, flat tube profiles with a profile depth of 16 mm ± 1 mm are used. The numbers of flat tubes of the first to fourth floods in the flow direction of the refrigerant when operating in the refrigeration system mode are in the ratio of 19: 13: 10: 6 to each other.

The first refrigerant passage 4 is connected to a likewise not shown formed as a refrigerant pipe pipe. The tube has an inner diameter which is greater than 10 mm and preferably 16 mm ± 1 mm. The second refrigerant passage 5 is also connected to a pipe, not shown, designed as a refrigerant pipe. The tube has an inner diameter which is greater than 6 mm and preferably 10 mm ± 1 mm or 13 mm ± 1 mm or 16 mm ± 1 mm.

The headers 2 . 3 are formed in one piece or two parts and have a width or a diameter which is greater than the profile depth of the flat tubes. In addition to at least one separating element 13 for closing the flow cross-section of the manifold 2 . 3 and the possible subdivision of the manifold 2 . 3 in separate volumes, shows each manifold 2 . 3 four plugs not shown for sealing the manifold 2 . 3 to the environment.

In the 3b . 3c are the dividers 13 out 3a each in detail with a rectilinearly movable closure element 14 shown.

The separation of the floods takes place in the headers 2 . 3 by means of the mechanical, differential pressure controlled movable separating elements 13 , which as valves during operation of the heat exchanger 1 closed in chiller mode and opened in heat pump mode. The movable dividers 13 are designed similarly as check valves.

The movable dividers 13 serve to divide the headers 2 . 3 in two areas with separate volumes for operation in the refrigeration system mode or the fluidic interconnecting the areas to a common volume in the heat pump mode. 3b shows the dividers 13 each in the closed state, in which the headers 2 . 3 have two separate volumes, while in 3c the separating elements 13 are shown in the open state.

Each separator 13 comprises a rectilinearly movable closure element 14 and a stopper member 15 , In the closed state of the separating element 13 lies the closure element 14 on the stop element 15 at.

When operating the heat exchanger 1 In refrigeration system mode, the shutter elements that can be moved in a straight line are 14 with a stop element 15 trained dividers 13 according to 3b closed. This after high-pressure compression by the first refrigerant passage 4 of the heat exchanger 1 in the upper area of the first manifold 2 entering, gaseous and hot refrigerant pushes the rectilinearly movable closure element 14 down and is split into the flow paths of the first tide. As a result of the pressure loss when flowing through the flow paths of the first flood, mixing, diverting and distributing to the flow paths of the second flood in the second manifold 3 and flowing through the flow paths of the second flood becomes the separating element 13 in the first manifold 2 On both sides with refrigerant at different pressures applied, wherein the differential pressure is the closure element 14 to the stop element 15 pushes and the separator 13 closes. The same applies to the separating element 13 in the second manifold 3 , The heat exchanger 1 is therefore flowed through in three streams. The refrigerant enters after the heat release through the second refrigerant passage 5 in the liquid or liquid / vapor state from the heat exchanger 1 out.

When operating the heat exchanger 1 in heat pump mode are the separators 13 with the straight-line shutter elements 14 according to 3c open. This through the second refrigerant passage 5 in the lower area of the second manifold 3 of the heat exchanger 1 entering, two-phase refrigerant pushes the rectilinearly movable closure element 14 upward and is divided into the flow paths of the three floods. The refrigerant is distributed throughout the entire second manifold 3 into the flow paths of the heat exchanger 1 and flows through all the flow paths in parallel. Due to the pressure of the incoming refrigerant, the closure element becomes 14 from the stop element 15 pushed away. The separating element 13 it is open. Because of the pressure loss from entering the refrigerant through the second refrigerant passage 5 until the exit of the refrigerant through the first refrigerant passage 4 the pressures on the upper side of the closure elements 14 are always lower than on the bottom, the closure elements remain 14 opened in heat pump mode due to the differential pressure. The heat exchanger 1 is thus flowed through in a single flow. The refrigerant passes through the first refrigerant passage after heat application 4 in the gaseous state from the heat exchanger 1 out.

The linearly movable closing elements 14 are designed such that the resulting force of gravity, flow forces and compressive forces causes an opening and closing.

4a shows the arrangement of the movable separating element 13 within a manifold 2 . 3 in the assembled state of the heat exchanger 1 , The illustrated section of the manifold 2 . 3 has a refrigerant passage 4 . 5 and a slotted outer wall. Through the slotted openings 16 in the outer wall are the flow paths of the floods forming flat tube profiles 17 introduced. The flat tube profiles 17 are at least with a depth of insertion of up to 10 mm, preferably 8 mm, in the headers 2 . 3 plugged in. The movable separating element 13 is also through a slotted opening, however, not shown in the manifold 2 . 3 inserted.

The flat tube profiles 17 and that the stop element 15 forming baffle of the separating element 13 be with the outer wall of the manifold 2 . 3 soldered. The baffle 15 is with the locking element 11 locked in the outer wall. The locking element 11 is on the slotted openings 16 for introducing the separating element 13 into the manifold 2 . 3 opposite side inserted into the outer wall. The trained as a strike plate rectilinear closure element 14 does not lie on the stop element 15 at, hereinafter also referred to as baffle, the movable separating element 13 it is open. In the opened state of the separating element 13 lies the movable closure element 14 in the collecting pipe 2 . 3 inserted flat tube profile 17 at. The flat tube profile 17 is thus at the same time as a stop for the closure element 14 in the opened state of the separating element 13 educated.

The separating element 13 is used in the manufacture of the heat exchanger 1 on the holding element 12 held and into the slotted headers 2 . 3 introduced. The locking element 11 serves as the static separator 7 out 2 , the fixation of the separating element 13 inside the manifold 2 . 3 during production. After insertion of the separating element 13 in the headers 2 . 3 the components are manifold 2 . 3 , Flat tube profiles 17 and stop element 15 soldered together.

In the 4b . 4c is the movable separating element 13 out 4a shown in detail, where 4b a front view and 4c a rear view of the separating element 13 shows. The movable separating element 13 points with the strike plate 14 and the baffle 15 two separately formed elements, which are preferably made by stamping sheet metal and formed symmetrically with respect to a plane of symmetry. The baffle 15 is made of a solderable material, preferably AA3003, with a coating, preferably made of AA4045, with a material thickness of at least 0.2 mm. The thickness of the baffle may vary in the range of 0.2 mm to 2.5 mm, preferably in a range of 0.4 mm to 2.3 mm. The striking plate 14 is in comparison to a non-solderable material, preferably stainless steel, for example AlSi 304 ( DIN 1.4301 ), having a material thickness of at least 0.2 mm, preferably in a range of 0.3 mm to 0.5 mm.

The baffle 15 has on the edge a circumferential outer contour, which takes into account tolerances of the inner contour of the manifold 2 . 3 is modeled. In addition, the outer contour of the baffle 15 with a locking element 11 and a holding element 12 provided, which are arranged on the plane of symmetry. The locking element 11 is opposite to the holding element 12 aligned. In addition to the outer contour has the baffle 15 an inner contour 18 in the form of a four-leaf clover, which as a continuous opening through the baffle 15 opens a flow cross-section. The through hole is perpendicular to the baffle 15 aligned plane. The striking plate 14 has a peripheral peripheral contour 19 also in the form of the four-leaf clover, which takes into account tolerances of the inner contour 18 of the deflector 15 is modeled. The outer contour 19 of the strike plate 14 has larger dimensions than the inner contour 18 of the deflector 15 so that the strike plate 14 in the closed state of the separating element 13 at the baffle 15 is applied. This will be the entire inner contour 18 of the deflector 15 from the outer contour 19 of the strike plate 14 covered. The tolerances of the dimensions of the outer contour 19 of the strike plate 14 and the inner contour 18 of the deflector 15 are about 0.1 mm, leaving a gap between the manifold 2 . 3 and the strike plate 14 the movement of the strike plate 14 allowed.

The inner contour 18 of the deflector 15 and the outer contour 19 of the strike plate 14 are essentially round and have on the one hand formations 20 and on the other hand cuts 21 on. The striking plate 14 is at the outer contour 19 with four cuts 21 provided, which is evenly spaced from each other, starting from the outer edge, in the direction of the center of the striking plate 14 extend. The incisions end here 21 after about one third of the diameter of the base of the strike plate 14 so that through the cuts 21 resulting portions of the strike plate 14 im to the center aligned aligned area are formed. The area of the incisions 21 from the original essentially round outer shape of the strike plate 14 deducted area is less than the total area of a strike plate with the same diameter without cuts. The striking plate 14 is according to 4c with a guide element 22 Mistake. The guide element 22 is perpendicular to the strike plate 14 aligned plane and aligned from the center of the strike plate 14 arranged extending in the longitudinal direction L. The form of a pin having guide element 22 is formed with a deviating from the circular cross section, which may for example be polygonal or oval.

The baffle 15 indicates the inner contour 18 four formations 20 on, which is equally spaced from each other, from the outside in the direction of the center of the baffle 15 extend. The formations end here 20 each after about one third of the diameter of the inner contour 18 of the deflector 15 , The dimensions of the formations 20 of the deflector 15 correspond to the dimensions of the incisions 21 of the strike plate 14 plus the tolerances for overlapping the contours 18 . 19 for closing the separating element 13 ,

The formations 20 the inner contour 18 of the deflector 15 and the guide element 22 of the strike plate 14 are each formed such that the guide element 22 on the front sides of the formations 20 is applied and thereby guided during the movement. The striking plate 14 is thereby against rotation against the baffle 15 held, because the guide element 22 the deviating from the round cross section, according to 4c has a square, cross-section. The straight faces of the formations 20 the inner contour 18 of the deflector 15 lie on the side edges of the square cross-section of the guide element 22 flat, so that the guide element 22 only in its longitudinal direction L is displaceable.

In the 5a . 5b . 5c . 5d . 5e is the movable separating element 13 ' shown in a further embodiment, wherein 5a a view of the installable partition 13 ' . 5b an exploded view to view the individual components, the 5c , and 5d each a sectional view and 5e show a construction sketch in plan view. 5c shows the separator 13 ' in the open and 5d in the closed state.

The stop element 15 ' indicates the area 8th with the border 9 on, which in turn with a locking element 11 and a holding element 12 is trained. The area 8th is centered with an inner contour 18 ' provided in the form of a circular opening. The circular opening extends as a passage over much of the area 8th , The area 8th points at the transition to the border 9 evenly distributed over the circumference arranged guide elements 23 on. The four step-shaped guide elements 23 are each provided as a circle segments with a step. The circle-center-oriented, circular arc-shaped first surfaces of the step, which on the surface 8th sit, serve the leadership of the rectilinearly movable closure element 14 ' , The aligned to the longitudinal direction L surfaces and the center of the circle aligned, circular arc-shaped surfaces of the step, which are in communication with the border, are as a support and attachment of the second stop element 24 educated. The second stop element 24 During production or assembly concentric with the center of the circle formed as a circle segments guide elements 23 on the heels of the steps of the guide elements 23 put on and soldered. The second stop element 24 is then at the level of the step spaced from the first stop element 15 ' arranged. The distance of the stop elements 15 ' . 24 determines the extent of movement of the closure element 14 ' ,

In the space between the surface 8th of the first stop element 15 ' which is the baffle 15 ' corresponds, and the second stop member 24 is the rectilinearly movable closure element 14 ' which is the strike plate 14 ' corresponds, arranged. The closure element 14 ' becomes movable between the stop elements 15 ' . 24 held and at the center of the circle aligned, circular arc-shaped surfaces of the first stage of the guide elements 23 guided. The arcuate surfaces of the first stage of the guide elements 23 and the side surface of the closure element 14 ' correspond with each other and ensure a leadership.

The circular trained second stop element 24 has openings at the outer periphery 25 in the form of holes or punched on. The radius of the stop element 24 corresponds to the radius of the circular center point towards aligned, circular arc-shaped surface of the step of the guide element 23 , which are in connection with the border, plus a tolerance for mounting and soldering together the stop elements 15 ' . 24 ,

The aligned in the longitudinal direction L openings 25 are so on the stop element 24 arranged and each formed with a diameter that when applying the closure element 14 ' on the stop element 24 to 5c at least a part of the openings 25 or the entire openings 25 from the closure element 14 ' are not covered and remain open.

The closure element 14 ' is freely movable between two end positions, wherein it is in the first end position on the first stop element 15 ' whatever is wrong 5d emerges, and formed as an opening inner contour 18 ' closes. The diameter of the closure element 14 ' is therefore larger than the diameter of the opening. The closure element 14 ' lies on the surface 8th on. The separating element 13 ' is closed. In the second end position is the closure element 14 ' according to 5c on the second stop element 24 and gives the inner contour 18 ' of the first stop element 15 ' free. Because at the same time the openings 25 the second stop element 24 remain open at least partially, allow the open areas of the openings 25 a passage between the areas on either side of the partition 13 ' , In addition, between the periphery of the stop element 24 and the outline 9 the stop element 15 ' A gap 26 formed, in the circumferential direction of the stop element 24 only through the guide elements 23 is interrupted. The gap 26 poses next to the openings 25 an additional passage for the fluid. The fluid flows in the direction indicated by arrows flow direction 6 through the separating element 13 ' therethrough. The separating element 13 ' it is open.

The decreasing flow cross-section in the heat exchanger 1 in the flow direction of the refrigerant when operating in the refrigeration system mode, such as 3a based on the ratios of the number of flat tubes and the diameters of the refrigerant lines at the refrigerant passages 4 . 5 described, is used in addition to the distribution of the heat transfer surfaces for maximum heat output with minimal space requirements and to reduce the refrigerant side pressure loss during flow through the heat exchanger 1 , In 6 is a terminal block 28 with a short circuit line 29 shown. In addition to the occurring pressure loss of the refrigerant when flowing through the floods and the mixing, diverting and splitting in the headers 2 . 3 the refrigerant also flows through the terminal block 28 the refrigerant line 27 at the refrigerant passages 4 throttled. It is mainly the pressure loss when flowing through the terminal block 28 significantly, which is located in the heat pump mode outlet side. To minimize pressure loss, the port block is formed either with a larger flow area than a conventional port block or the conventional port block 28 comes with a short circuit line 29 Mistake. The short circuit line 29 It is also called a "jam tube" and provides a bypass from the manifold 2 to the connection block 28 This is the flow cross-section of the refrigerant passage 4 between the manifold 2 and the refrigerant line 27 around the cross-section of the short-circuit line 29 extended, without the flow cross-section of the refrigerant passage 4 to enlarge itself. The pressure loss when the refrigerant exits the heat exchanger 1 is reduced.

LIST OF REFERENCE NUMBERS

1

Heat exchanger

2

first manifold

3

second manifold

4

first refrigerant passage

5

second refrigerant passage

6

Flow direction of refrigerant

6 ^I

Flow direction of refrigerant in refrigeration system mode

6 ^II

Flow direction of refrigerant in heat pump mode

7

static separating element

8th

area

9

border

10

plane of symmetry

11

locking

12

retaining element

13, 13 '

movable separating element

14, 14 '

rectilinearly movable closure element, strike plate

15, 15 '

Stop element for closure element 14 , Baffle

16

slotted opening in the manifold 2 . 3

17

Flat tube profile

18, 18 '

inner contour of the baffle 15 . 15 '

19

outer contour of the striking plate 14

20

Formations of the inner contour 18

21

Incisions of the outer contour 19

22, 23

guide element

24

second stop element for closure element 14 '

25

opening

26

gap

27

Refrigerant line

28

terminal block

29

Short-circuit line

L

longitudinal direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1895255 B1 [0008]

Cited non-patent literature

• DIN 1.4301 [0063]

Claims (16)

Heat exchanger ( 1 ) of a refrigerant circuit of an air conditioning system of a motor vehicle, wherein the air conditioning system is designed for a combined operation in refrigeration and heating mode, comprising - a first manifold ( 2 ) and a second manifold ( 3 ), which are arranged spaced apart and aligned parallel to each other, - a first refrigerant passage ( 4 ) and a second refrigerant passage ( 5 ) to flow through the refrigerant, - flow paths, which are arranged as mutually parallel fluid connections between the headers ( 2 . 3 ) are formed and are each assigned to a flood, and - means for dividing the inner volume of at least one collecting tube ( 2 . 3 ) in independent areas, wherein - the heat exchanger ( 1 ) is formed mehrflutig and bi-directionally permeable and the flow direction of the refrigerant in the interior of the heat exchanger ( 1 ) is dependent on the operating mode, - in the flow direction of the refrigerant in the refrigeration system mode - the first flood of the heat exchanger ( 1 ) has a larger flow cross section and a larger heat transfer surface than the last flood and - the first refrigerant passage ( 4 ) for the inflow of the refrigerant has a larger or equal flow cross-section as the second refrigerant passage ( 5 ) to the outflow of the refrigerant. Heat exchanger ( 1 ) according to claim 1, characterized in that the first refrigerant passage ( 4 ) for flowing the refrigerant when operating in the refrigeration system mode has an inner diameter of greater than 8 mm. Heat exchanger ( 1 ) according to claim 1 or 2, characterized in that the second refrigerant passage ( 5 ) for discharging the refrigerant when operating in the refrigeration system mode has an inner diameter of greater than 6 mm. Heat exchanger ( 1 ) of a refrigerant circuit of an air conditioning system of a motor vehicle, comprising a collecting pipe ( 2 ), parallel flow paths and at least two refrigerant passages, wherein - the heat exchanger ( 1 ) is bidirectionally permeable and the flow direction of the refrigerant in the interior of the heat exchanger ( 1 ) depends on the operating mode of the air conditioning, - the refrigerant depending on the flow direction, the flow paths, the manifold ( 2 ) and the refrigerant passage ( 4 ) flows through one after another and - the refrigerant passage ( 4 ) with a terminal block ( 28 ) for connecting a refrigerant line ( 27 ), characterized in that between the collecting pipe ( 2 ) and the terminal block ( 28 ) as an additional fluid connection to the refrigerant passage ( 4 ) formed short-circuit line ( 29 ) is arranged. Heat exchanger ( 1 ) according to one of claims 1 to 4, characterized in that the fluid connections between the headers ( 2 . 3 ) arranged flow paths of flat tube profiles are formed, wherein the flat tube profiles have a depth of less than 20 mm. Heat exchanger ( 1 ) according to claim 5, characterized in that the heat exchanger ( 1 ) is designed to flow in two directions, wherein the ratio of the number of flat tube profiles of the first flood to the second flood is in the range of 3 to 5 in the flow direction of the refrigerant in the refrigeration system mode. Heat exchanger ( 1 ) according to claim 5, characterized in that the heat exchanger ( 1 ) is designed to flow in four-flow, wherein the ratio of the numbers of flat tube profiles of successively flowed through flows 19: 13: 10: 6 in the flow direction of the refrigerant in the refrigeration system mode. Device for subdividing the internal volume of a collecting tube ( 2 . 3 ) and for the flow deflection of the fluid in the manifold ( 2 . 3 ) of a heat exchanger ( 1 ), characterized in that within the collecting tube ( 2 . 3 ) at least one movable separating element ( 13 . 13 ' ) is arranged, wherein the movable separating element ( 13 . 13 ' ) - Based on the differential pressure principle is formed and depending on the orientation within the manifold ( 2 . 3 ) and adjoining pressure difference opens or closes an opening, - a movable closure element ( 14 . 14 ' ) and a stop element ( 15 . 15 ' ), wherein the closure element ( 14 . 14 ' ) in the closed state of the separating element ( 13 . 13 ' ) on the stop element ( 15 . 15 ' ) is present. Apparatus according to claim 8, characterized in that the stop element ( 15 . 15 ' ) an inner contour ( 18 . 18 ' ), wherein the inner contour ( 18 . 18 ' ) forms an opening as a flow cross-section for the fluid, which through the closure element ( 14 ) in the closed state of the separating element ( 13 . 13 ' ) is closed. Apparatus according to claim 8 or 9, characterized in that the closure element ( 14 . 14 ' ) is formed in a longitudinal direction L movable in a straight line. Device according to one of claims 8 to 10, characterized in that the separating element ( 13 . 13 ' ) Means for guiding the movement of the movable closure element ( 14 . 14 ' ) relative to the stop element ( 15 . 15 ' ) having. Device according to claim 11, characterized in that the inner contour ( 18 ) of the stop element ( 15 ) with formations ( 20 ) and the closure element ( 14 ) with a guide element ( 22 ) are formed, wherein the guide element ( 22 ) has the form of a pin which is perpendicular to the closure element ( 14 ) plane spanned in the longitudinal direction L extending on the closure element ( 14 ) is arranged and on the formations ( 20 ) is held movably in the longitudinal direction L, so that the formations ( 20 ) and the guide element ( 22 ) a guide for the movable closure element ( 14 ) train. Apparatus according to claim 11, characterized in that the separating element ( 13 ' ) with guide elements ( 23 ) for guiding the movable closure element ( 14 ' ) is formed, wherein the guide elements ( 23 ) - evenly around the circumference of the inner contour ( 18 ' ) of the stop element ( 15 ' ) on the stop element ( 15 ' ), are formed as circle segments with a step, wherein the circular center point towards aligned, circular arc-shaped surfaces of the step, which on the stop element ( 15 ' ), for guiding the movable closure element ( 14 ' ) are provided and with the side surface of the closure element ( 14 ' ), and - as a support and attachment of a second stop element ( 24 ) for the closure element ( 14 ' ) are formed. Apparatus according to claim 13, characterized in that the second stop element ( 24 ) - at the level of the step spaced from the first stop element ( 15 ' ), wherein the closure element ( 14 ' ) in the longitudinal direction L between the stop elements ( 15 ' . 24 ) is movably supported, and - is formed circular and arranged on the outer circumference, aligned in the longitudinal direction L openings ( 25 ), wherein the openings ( 25 ) are formed such that when the closure element ( 14 ' ) on the stop element ( 24 ) at least one part of the opening ( 25 ) release a passage. Device according to one of claims 11 to 14, characterized in that the means for guiding the movement of the closure element ( 14 . 14 ' ) relative to the stop element ( 15 . 15 ' ) are formed such a rotation of the closure element ( 14 . 14 ' ) to prevent. Heat exchanger ( 1 ) according to one of claims 1 to 7, characterized in that within a collecting tube ( 2 . 3 ), a device according to one of claims 8 to 15 is formed, so that the flow cross-section and / or the heat transfer surface are dynamically changeable.

Images